Hypertension (HTN) is one of the most preventable causes of cardiovascular and cerebrovascular disease, and one of the most important contributors to health disparities. Precision Medicine - with the associated attention to individual variability in living environment, to the experience of and the responses to this environment, to lifestyle, and to other contextual factors that act at the level of the individual and influence HTN risk - may hold the greatest promise for promoting health equity and reducing health disparities in HTN risk. Contextual factors can profoundly affect daytime ambulatory blood pressure measurement (ABPM), which is more closely associated with HTN risk than the resting clinic BP (CBP). ABPM provides a window into the ?personal? factors that influence BP during the day, and an earlier signal of HTN risk through the identification of individuals with ?nondipping? nocturnal BP, and with masked hypertension (MHT), a condition defined by hypertensive ABPM and normotensive CBP. Among the key factors for health disparities that may influence ABPM are exposure to racism, neighborhood environment and noise, and level of social support. While research has repeatedly shown these effects, health disparities persist, in large part because clinical care has not yet found a way to incorporate these factors for risk prediction and treatment at the individual level. We propose to examine momentary ambulatory blood pressure (ABPM) in relation to individual variability in environment, lifestyle, and related contextual factors, in the NIMHD-funded Eastern Caribbean Health Outcomes Research Network (ECHORN), a previously defined cohort of individuals of African and Hispanic descent at high HTN risk. We will develop individual level phenotypes of HTN risk, based on contextual factors and the momentary effects these have on ABP, using advanced analytic techniques. Specific Aims: 1.To examine the clustering of contextual factors captured using ecological momentary assessment (EMA), validated questionnaires, information about the built environment, and actigraphy data on sleep ? with momentary ABP over 24-hours; 2. To prospectively assess the contribution of contextual factors to trajectories of ABP over time, using advanced computational techniques to characterize contextual phenotypes associated with ABP trajectory over 2-years. Hypotheses: 1. Patterns of contextual factors associated with ABPM will define phenotypes of individuals with varying HTN risk. 2. Longitudinally assessed contextual phenotype will predict 2-year BP trajectories, i.e., changes in ABPM and resting CBP. Significance. By identifying actionable, individual level factors that increase HTN risk, the results of the proposed study will address a critical knowledge gap concerning health disparities and directly lead to the development of Precision Medicine based screening tools and risk prediction models to inform personalized intervention strategies for individuals at highest risk for HTN.